var OriginTitile = document.title;
var titleTime;
document.addEventListener('visibilitychange', function () {
    if (document.hidden) {
        document.title = '(つェ⊂) 我藏好了哦~ ';
        clearTimeout(titleTime);
    } else {
        document.title = 'o(^▽^)o 被你发现啦~ ';
        titleTime = setTimeout(function () {
            document.title = OriginTitile;
        }, 2000);
    }
});